Hackers rally to support WikiLeaks: Top 5 recent attacks

In an effort nicknamed "Operation Payback," a loose association of hackers called "Anonymous" has been targeting the websites of companies and organizations that have cut ties with WikiLeaks by overwhelming their sites with traffic, prompting them to shut down. Twitter and Facebook have blocked accounts for Anonymous, citing the illegality of their attacks as a terms-of-service violation. WikiLeaks' Facebook and Twitter accounts remain up and running.

“Of course, Anonymous is expected to keep creating new accounts as quickly as Facebook and Twitter squash them; it’s a bit like Whack-a-Mole or doing battle with a hydra, in that sense,” said social media news website Mashable. "Fighting Anonymous is a task we wouldn’t wish on anyone."

Below are some of the most notable attacks.

Newscom

A screenshot of WikiLeaks' homepage on Dec. 9.

Mastercard and Visa

Mastercard was the first credit-card company to come under attack by hackers, and attacks on Visa soon followed – both launched in retaliation for the companies’ refusal to process donations to WikiLeaks. At various points Wednesday, parts or all of their websites were down, MSNBC reported.

NPR reported Thursday that WikiLeaks’ payment processor, Iceland's DataCell ehf, is preparing to sue both companies for their decision to block the funds, which it claimed is costing the company money.

"It's difficult to believe that such a large company as Visa can make a political decision," [CEO Andreas] Fink said in a telephone interview from Switzerland. In an earlier statement, his company had defended the WikiLeaks, saying that "it is simply ridiculous to think WikiLeaks has done anything criminal."